Maintenance; Introduction; Prepare Maintenance - A.O. Smith TWI 35-130 Instruction Manual

10
10.1

Introduction

10.2 Prepare

maintenance

Instruction manual TWI 35-130 G/TWI 45-190 G
Maintenance
Service shall be carried out at least once a year both on the gas side and on the
water side. The frequency of the maintenance depends, among other things, on
the water quality, the average number of operating hours per day and the set
water temperature.
Remark
Regular maintenance lengthens the life of the device. For determining
the correct maintenance frequency, it is advised to have the service and
maintenance engineer check the gas side and the water side of the device
three months after installation. The maintenance frequency can be determined
on the basis of this check.
Proceed as follows for testing the proper functioning of all components:
1. Maximally turn the thermostat counterclockwise.
2. Wait until the fan stops.
3. Turn the thermostat to its original position. Then draw off water to create a
heat demand.
4. Check if the heating cycle runs correctly
5. Check the CO -value and adjust this if necessary
2
the CO -value").
2
6. Check all parts of the fl ue gas discharge system for proper fastening.
7. Check the pressure difference of the pressure switch (see the table).
Clean the heat exchanger and burner if the pressure difference is too low
(10.4.2 "Clean the burner" AND 10.4.3 "Clean heat
Pressure difference of air pressure switch
Device Measured pressure difference over air pressure switch
TWI 35-130 ≥ 730 Pa
TWI 45-190 ≥ 400 Pa
8. Test the functioning of the expansion valve of the protected cold supply
setup. The water has to fl ow out in a forceful jet.
9. Test the functioning of the T&P valve (if applicable). The water has to fl ow
out in a forceful jet.
10. Check the discharge pipes of the expansion valve and remove any
present scale deposits.
11. Drain the device (see Drain).
(7.3 "Heating cycle of the device").
(3.11 "Check and adjust
exchanger").
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